1. Field of the Invention
This invention relates to the selective chemical etching of polyimide-silicone copolymers for patterning thereof.
2. Description of the Prior Art
In the copending patent application of Abe Berger entitled "Polyimide-Silicone Copolymers For Coating Semiconductor Junctions", U.S. Ser. No. 652,092 the method of making the material and its application to selective surfaces areas of electronic devices is taught. After the copolymer material is applied to surface areas it becomes necessary on occasion to open windows in the coating and/or to remove material from selective areas. It is desirable that the removal of the unwanted portions of the copolymer material be done as quickly and as easily as possible to facilitate semiconductor device processing. It is also most desirable to maintain the registry and dimensions of the pattern.
An object of this invention is to provide a new and improved method to pattern a layer of a cured polyimide-silicone copolymer material.
Another object of this invention is to provide a new and improved method for selective chemical etching of a layer of a cured polyimide-silicone copolymer material which embodies titanium metal as a masking material.
A further object of this invention is to provide a new and improved method for selective chemical etching of a layer of a cured polyimide-silicone copolymer material which opens windows in the layer, the edges of which are substantially free of undercutting.
Other objects of this invention will, in part, be obvious and will in part, appear hereinafter.